> By your logic, chrome could choose to stop supporting literally anything (including HTML) in their "browser" and not have done anything that we can object to.

Literally this. Microsoft used to ship a free web browser. Then they stopped. That's not something anybody can object to.

> because the IE specific stuff they didn't implement was never part of the open web standards, but rather stuff Microsoft unilaterally chose to add.

Standards aren't holy books. It's actually more important to support real customer use cases than to follow standards.

But you know this. If standards are more important that real use cases, then the fact that XSLT has been removed from the html5 standard is enough justification to remove it from Chrome.